1,4-Diaryl-2-fluoro-1,3-butadiene compounds, methods for their preparation, and their use as intermediates in the preparation of 1,4-diaryl-2-fluoro-2-butene insecticidal and acaricidal agents are described in EP 811593-A1. The methods described in EP 811593-A1 for the preparation of 1,4-diaryl-2-fluoro-1,3-butadiene compounds require the use of phosphonium halide compounds. However, these methods are not entirely satisfactory because the required phosphonium halide compounds are relatively expensive and produce undesirable by-products which are difficult to remove from the 1,4-diaryl-2-fluoro-1,3-butadiene compounds. Accordingly, a need exists in the art for an improved process for the preparation of 1,4-diaryl-2-fluoro-1,3-butadiene compounds which avoids the use of phosphonium halide compounds.
It is, therefore, an object of the present invention to provide an improved process for the preparation of 1,4-diaryl-2-fluoro-1,3-butadiene compounds which avoids the use of phosphonium halide compounds.
It is also an object of the present invention to provide an improved process for the preparation of 1,4-diaryl-2-fluoro-2-butene compounds.
Other objects and advantages of the present invention will be apparent to those skilled in the art from the description below and the appended claims.
The present invention provides a new process for the preparation of 1,4-diaryl-2-fluoro-1,3-butadiene compounds of the structural formula I 
wherein
R is C1-C4alkyl, C1-C4haloalkyl, C3-C6cycloalkyl or C3-C6halocycloalkyl;
Ar is phenyl optionally substituted with any combination of from one to three halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups,
1- or 2-naphthyl optionally substituted with any combination of from one to three halogen, C1-C4alkyl, C1-C4haloalkyl C1-C4alkoxy or C1-C4haloalkoxy groups, or
a 5- or 6-membered heteroaromatic ring optionally substituted with any combination of from one to three halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups; and
Ar1 is phenoxyphenyl optionally substituted with any combination of from one to six halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups,
phenyl optionally substituted with any combination of from one to five halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy, or C1-C4haloalkoxy groups,
biphenyl optionally substituted with any combination of from one to five halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups,
phenoxypyridyl optionally substituted with any combination of from one to five halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups,
benzylpyridyl optionally substituted with any combination of from one to five halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups,
benzylphenyl optionally substituted with any combination of from one to five halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups,
benzoylphenyl optionally substituted with any combination of from one to five halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups,
1- or 2-naphthyl optionally substituted with any combination of from one to three halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups, or
a 5- or 6-membered heteroaromatic ring optionally substituted with any combination of from one to three halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups,
which process comprises reacting an arylmethanesulfonyl fluoride or arylmethanephosphonate compound of the structural formula II
Ar1CH2Yxe2x80x83xe2x80x83(II)
wherein Y is SO2F or P(O) (OR1)2, R1 is C1-C4alkyl, and
Ar1 is as hereinbefore defined with a 3-aryl-2-fluoropropenal compound of the structural formula III 
wherein R and Ar are as hereinbefore defined in the presence of a base.
The present invention further provides a new process for the preparation of 1,4-diaryl-2-fluoro-2-butene compounds of the structural formula IV 
wherein
R is C1-C4alkyl, C1-C4haloalkyl, C3-C6cycloalkyl or C3-C4halocycloalkyl;
Ar is phenyl optionally substituted with any combination of from one to three halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups,
1- or 2-naphthyl optionally substituted with any combination of from one to three halogen, C1-C4alkyl, C1-C4haloalkyl C1-C4alkoxy or C1-C4haloalkoxy groups, or
a 5- or 6-membered heteroaromatic ring optionally substituted with any combination of from one to three halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups; and
Ar1 is phenoxyphenyl optionally substituted with any combination of from one to six halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups,
phenyl optionally substituted with any combination of from one to five halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy, or C1-C4haloalkoxy groups,
biphenyl optionally substituted with any combination of from one to five halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups,
phenoxypyridyl optionally substituted with any combination of from one to five halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups,
benzylpyridyl optionally substituted with any combination of from one to five halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups,
benzylphenyl optionally substituted with any combination of from one to five halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups,
benzoylphenyl optionally substituted with any combination of from one to five halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups,
1- or 2-naphthyl optionally substituted with any combination of from one to three halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups, or
a 5- or 6-membered heteroaromatic ring optionally substituted with any combination of from one to three halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups,
which process comprises the steps of:
(a) reacting an arylmethanesulfonyl fluoride or arylmethanephosphonate compound of the structural formula II
Ar1CH2Yxe2x80x83xe2x80x83(II)
wherein Y is SO2F or P(O) (OR1)2, R1 is C1-C4alkyl, and
Ar1 is as described above with a 3-aryl-2-fluoropropenal compound of the structural formula III 
wherein R and Ar are as described above in the presence of a base to form a 1,4-diaryl-2-fluoro-1,3-butadiene compound of the structural formula I 
(b) reacting the 1,4-diaryl-2-fluoro-1,3-butadiene compound with: (1) an alkaline earth metal in the presence of a protic solvent, or (2) an alkali metal in the presence of an aprotic solvent.
In a preferred embodiment of the present invention, the 1,4-diaryl-2-fluoro-1,3-butadiene compounds of formula I are prepared by reacting an arylmethanesulfonyl fluoride or arylmethanephosphonate compound of formula II with a 3-aryl-2-fluoropropenal compound of formula III and a base, preferably at a temperature ranging from about xe2x88x9278xc2x0 C. to 150xc2x0 C., more preferably from about xe2x88x9220xc2x0 C. to about 100xc2x0 C., in the presence of a solvent.
In another preferred embodiment of the present invention, the 1,4-diaryl-2-fluoro-2-butene compounds of formula IV are prepared by reacting an arylmethanesulfonyl fluoride or arylmethanephosphonate compound of formula II with a 3-aryl-2-fluoropropenal compound of formula III and a base, preferably at a temperature ranging from about xe2x88x9278xc2x0 C. to about 150xc2x0 C., more preferably from about xe2x88x9220xc2x0 C. to about 100xc2x0 C., in the presence of a solvent to form a 1,4-diaryl-2-fluoro-1,3-butadiene compound of formula I, and reacting the formula I butadiene compound with an alkaline earth metal in the presence of a protic solvent.
Most advantageously, the present invention provides a process for the preparation of 1,4-diaryl-2-fluoro-1,3-butadiene compounds which avoids the use of phosphonium halide compounds.
The product formula I and IV compounds may be isolated by diluting the reaction mixture with water and extracting the product with a suitable extraction solvent. In the isolation procedure, conventional extraction solvents such as diethyl ether, ethyl acetate, toluene, methylene chloride, and the like, and mixtures thereof may be utilized.
Bases suitable for use in the present invention include, but are not limited to, alkali metal hydrides such as sodium hydride and the like; alkali metal C1-C6alkoxides such as sodium methoxide and the like; alkali metal hydroxides such as potassium hydroxide, sodium hydroxide and the like; alkali metal carbonates such as potassium carbonate, sodium carbonate and the like; alkaline earth metal hydroxides such as calcium hydroxide and the like; alkaline earth metal carbonates such as calcium carbonate and the like; lithium bases such as alkyllithiums including n-butyllithium, sec-butyllithium, tert-butyllithium, methyllithium and the like, lithium dialkylamides including lithium diiso-propylamide and the like, and lithium cyclicamides including lithium tetramethylpiperidine and the like; and tri(C1-C6alkyl)amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, diisopropylethylamine and the like. Preferred bases include alkali metal C1-C6alkoxides and alkali metal carbonates.
Solvents useful in the preparation of the formula I compounds of this invention include, but are not limited to, carboxylic acid amides such as N,N-dimethylformamide, N,N-dimethylacetamide and the like; ethers such as diethyl ether, tetrahydrofuran, dioxane, 1,2-dimethoxyethane and the like; nitrites such as acetonitrile, propionitrile and the like; dialkyl sulfoxides such as dimethyl sulfoxide and the like; aromatic hydrocarbons such as toluene, benzene, xylenes, mesitylene and the like; and C1-C6alcohols such as methanol, ethanol, isopropanol, propanol and the like; and mixtures thereof. Preferred solvents includes ethers and nitrites.
Protic solvents suitable for use in this invention include, but are not limited to, C1-C6alcohols such as methanol, ethanol and the like. Preferred protic solvents include methanol and ethanol.
Aprotic solvents include, but are not limited to, ammonia; and ethers such as diethyl ether, tetrahydrofuran, dioxane, 1,2-dimethoxyethane and the like.
Alkaline earth metals suitable for use in the preparation of the formula IV compounds include, but are not limited to, magnesium and calcium with magnesium being preferred. Alkali metals include, but are not limited to, lithium, sodium and potassium.
In another preferred embodiment of the present invention, the arylmethanesulfonyl fluoride or arylmethanephosphonate compound is reacted with the 3-aryl-2-fluoropropenal compound and the base in the presence of a catalytically effective amount of a phase transfer catalyst. Phase transfer catalysts suitable for use in this invention include, but are not limited to, crown ethers such as 18-crown-6, 15-crown-5, 12-crown-4 and the like; quaternary ammonium salts such as tricaprylymethylammonium chloride and the like; and cryptands such as 1,4,10-trioxa-7,13-diazacyclo-pentadecane, 4,7,13,18-tetraoxa-1,10-diazabicyclo-[8.5.5]eicosane, 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane, 5,6-benzo-4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane and the like.
In a preferred process of this invention, R1 is an ethyl group when an arylmethanephosphonate compound is used to prepare the formula I compounds.
Preferred formula I and II compounds which may be prepared by the processes of this invention are those wherein
R is C1-C4alkyl, C1-C4haloalkyl, C3-C6cycloalkyl or C3-C6halocycloalkyl;
Ar is phenyl optionally substituted with any combination of from one to three halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups; and
Ar1 is 3-phenoxyphenyl optionally substituted with any combination of from one to six halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups,
3-biphenyl optionally substituted with any combination of from one to five halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups, or
3-benzylphenyl optionally substituted with any combination of from one to five halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups.
Highly preferred 1,4-diaryl-2-fluoro-1,3-butadiene and 1,4-diaryl-2-fluoro-2-butene compounds which may be prepared by the processes of this invention are those wherein
R is isopropyl or cyclopropyl;
Ar is phenyl optionally substituted with any combination of from one to three halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups; and
Ar1 is 3-phenoxyphenyl optionally substituted with any combination of from one to six halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy groups.
The present invention is especially useful for the preparation of
1-(p-chlorophenyl)-1-cyclopropyl-2-fluoro-4-(4-fluoro-3-phenoxyphenyl)-1,3-butadiene; and
1-[1-(p-chlorophenyl)-2-fluoro-4-(4-fluoro-3-phenoxyphenyl)-2-butenyl]cyclopropane.
In formulas I and IV above, the 5- and 6-membered heteroaromatic ring may suitably be a ring containing one to four heteroatoms selected from N, O and S, wherein the heteroatoms may be the same or different, e.g. the rings include, but are not limited to, pyridyl, pyrazolyl, imidazolyl, triazolyl, isoxazolyl, tetrazolyl, pyrazinyl, pyridazinyl, triazinyl, furanyl, thienyl and thiazolyl rings each optionally substituted a as described in formulas I and IV above.
Exemplary of xe2x80x9chalogenxe2x80x9d as used herein are fluorine, chlorine, bromine and iodine. The terms xe2x80x9cC1-C4haloalkylxe2x80x9d, xe2x80x9cC3-C6halocycloalkylxe2x80x9d and xe2x80x9cC1-C4haloalkoxyxe2x80x9d are defined as a C1-C4alkyl group, a C3-C6cycloalkyl group and a C1-C4alkoxy group substituted with one or more halogen atoms, respectively, wherein the halogen atoms may be the same or different.
When used herein as a group or part of a group the term xe2x80x9calkylxe2x80x9d includes straight or branched chain alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl and t-butyl. When used herein as a group or part of a group the term xe2x80x9ccycloalkylxe2x80x9d incudes cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.
Groups containing two or more rings, such as biphenyl, phenoxypyridyl and benzylphenyl, which may be substituted, may be substituted on either ring unless otherwise specified herein.
Starting arylmethanesulfonyl fluoride compounds of formula II wherein Y is SO2F may be prepared, as shown in Flow Diagram I, by reacting an arylmethanebromide compound of the structural formula V with sodium sulfite to form a sodium arylmethanesulfonate compound of the structural formula VI, reacting the formula VI sulfonate compound with phosphorous pentachloride to form an arylmethanesulfonyl chloride compound of the structural formula VII, and reacting the sulfonyl chloride compound with potasium fluoride. 
Starting arylmethanephosphonate compounds of formula II wherein Y is P(O) (OR1)2 may be prepared as shown in Flow Diagram II, by reacting an arylmethanebromide compound of the structural formula V with a tri-(C1-C4alkyl)phosphite compound of the structural formula VIII. 
3-Aryl-2-fluoropropenal compounds of structural formula III may be prepared according to the procedures described in EP 811593-A1.